Giant Gravel Batteries to Improve Renewable Energy Technologies

An avant-garde technology is being implemented into wind turbines and solar panels which may potentially offer secure energy storage even when wind and sunlight is not readily available. By allowing electricity to be stored while environmental elements are out of reach, giant-sized batteries made with gravel are anticipated to improve renewable energy generation and will dampen constant criticism of opponents who claim that the renewable energy technology is not economically viable. “If you bolt this to a wind farm, you could store the intermittent and relatively erratic energy and give it back in a reliable and controlled manner,” says Jonathan Howe, founder of Isentropic and previously an engineer at the Civil Aviation Authority. The gravel-based battery would, according to Isentropic, be capable of storing energy equal to that of the former all while using less space – and cash. The company’s technology begins with two silos filled with a pulverized rock such as gravel. Then, electricity is employed to heat and pressurize argon gas which is fed into one of the silos; and, by the time the gas escapes the chamber, it has cooled to an ambient temperature while the gravel itself is heated to 500°C (or 932°F).

The gas is then directed into the second silo where it expands back to normal atmospheric pressure. This stage acts as an oversized refrigerator – causing the gas and rock temperature inside the second chamber to drop to -160°C (or -256°F). Any energy originally produced by the wind turbines is stored as a temperature variation between the two rock-filled silos – so to release the energy, the cycle is reversed, and as the energy changes from hot to cold it powers a generator that makes electricity. Isentropic guarantees an energy efficiency of up to 80 percent and, because gravel is inexpensive, the cost of a system per-kilowatt-hour of storage would be between $10 and $55. According to Howe, the energy in the sizzling silo can be easily stored for extended periods of time; and by his calculations, a silo that stands 50m tall and was 50m in diameter would only lose half of its energy through its walls if left undisturbed for three years. David Bott, director of innovation programs at the Technology Strategy Board, one of the sponsors of the 2010 Clean and Cool trade mission said: “Isentropic have done something very exciting, by revisiting scientific theory and coming up with a new technology that answers the need to match the generation of electricity with its use. For instance, the system could enable the more efficient use of wind power, by storing the energy generated by a turbine until it is needed. We need ways to store the energy we generate when we have a surplus, so that it can be used when we need extra and this innovative new system could provide the answer.”

Solar technology advancements have come a long way. It’s great to have so many options with renewable energy.

Kristine

# 27 April 2010 at 5:56 PM

tb said:

Make it even more efficient, bury it. Don’t turbines sit on top of a large concrete piling that requires excavation already?

# 9 June 2010 at 4:37 AM

Uncle B said:

As electric cars proliferate, storage of excess wind power will be facilitated by their very batteries. Battery cars will proliferate as oil prices in America rise. More Wind and Solar developments will follow – the greedy Capitalist will make it so! As supplies of oil(finite in this world) dwindle, and as Asian demand offers higher value in Yuan for each barrel of oil produced, oil prices in U.S. dollars will rise. A “Balance Point” in America will be reached where it is more economic to use battery cars and nuclear/electric sourced electric bullet train networks, a point where Solar, Wind, Wave, Hydro, Tidal, Geothermal and Nuclear produced electricity will replace oil due to lower cost. In the following half century these changes will become more apparent, and even sewage will be bio-gassed for its consumer gas as well as offal and Factory Farm wastes. For now, OPEC, Mexico and Canada maintain oil prices at all time lows to make market for themselves and to keep Yankee Doodle hooked on oil! Canadian Tar Sands will be exploited with nuclear heat to supply America’s huge appetite for oil soon, and as long as the world can keep the blinders on the Americans they will have a market for this nasty product. Counter these ideas with the notion that Solar, Wind, Wave, Hydro, Tidal and Geothermal electricity are all re-newable, or perpetual, if you please, and very clean, and you have the battle in America for the 21st Century outlined.

Remember the harsh Corporatist interests – Google, Torrent, the movie, “Who Stole The Electric Car” to understand the powers involved in the EV-1, America’s first successful car. Those proven effective batteries are still in “Patent Limbo” owned by the oil barons! So: Who is screwing who in America? Watch out for the Corporatists and their powerful lobbies, they do more damage to the average Patriot than he knows!